1. Field of the Invention
The present invention relates to a semiconductor integrated circuit device. In particular, the present invention relates to a semiconductor integrated circuit device including a data rewritable non-volatile semiconductor memory device.
2. Description of the Related Art
An electrically rewritable non-volatile semiconductor memory device, for example, a flash memory writes data in units of a page. In the write operation, program and verify are repeated. In the following description, the number of repeat times is called the loop count. The loop count is not infinite, but limited in some degree. If it is determined that write is sufficiently made before the program loop reaches the limited number of times, write status is set as “pass”, and then, write with respect to the page ends. Conversely, if the program loop reaches the limited number of times in a state that write is not sufficient, write status is set as “fail”, and then, write with respect to the page ends.
In the flash memory, for example, a NAND flash memory, several pages, for example, 32 pages, are collected to form a unit calling a block. The block is the data erase minimum unit.
As one of the specifications of a memory card, there is an average write speed of a block. If it is desired to determine the average write speed, it is recommended to measure the loop count of the entirety of one block. In order to determine the write speed, the following operation is required. Specifically, the loop count is measured when every write is completed with respect to one page. The foregoing operation is continued until write is completed with respect to the entirety of one block. Finally, the loop count thus measured is added together to obtain the total number of times.
However, according to the method of measuring the loop count when every write to one page is completed, much time is spent.    Reference document: JPN. PAT. APPLN. KOKAI Publication No. 5-314780